文献类型：期刊文献

英文题名：Peroxometalates Immobilized on Magnetically Recoverable Catalysts for Epoxidation

作者：Qiao, Yunxiang[1,2];Li, Huan[1];Hua, Li[1];Orzechowski, Lars[2];Yan, Kai[2,3];Feng, Bo[1];Pan, Zhenyan[1];Theyssen, Nils[2];Leitner, Walter[2,3];Hou, Zhenshan[1]

机构：[1]E China Univ Sci & Technol, Key Lab Adv Mat, Res Inst Ind Catalysis, Shanghai 200237, Peoples R China;[2]Max Planck Inst Kohlenforsch, D-45470 Mulheim, Germany;[3]Rhein Westfal TH Aachen, Inst Tech & Makromol Chem, Lehrstuhl Tech Chem & Petrolchem, D-52064 Aachen, Germany

年份：2012

卷号：77

期号：12

起止页码：1128

外文期刊名：CHEMPLUSCHEM

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000312549500010)】；

基金：We are grateful for the support from the National Natural Science Foundation of China (no. 21073058), the Research Fund for the Doctoral Program of Higher Education of China (20100074110014), the Fundamental Research Funds for the Central Universities, China Scholarship Council, and the Max Planck Society. We also gratefully acknowledge Dr. Christophe Fares, Dr. Bodo Zibrowius, and Bernd Spliethoff for helpful and enthusiastic discussions as well as support from Jutta Rosentreter.

语种：英文

外文关键词：covalent bonds; epoxidation; hydrogen bonds; magnetic materials; nanoparticles; peroxometalates

摘要：Magnetically separable catalysts were prepared and employed for the epoxidation of olefins with hydrogen peroxide. In all cases the magnetic core was firstly covered with a silica layer to prevent iron ion-initiated decomposition of hydrogen peroxide. The catalytic active species, an ionic liquid-type peroxotungstate, was then immobilized either by hydrogen bonding (catalyst 1) or by covalent Si?O linkage (catalyst 2). In addition to a thorough characterization by FT-IR, XRD, NMR, DRIFT, XPS, and TEM, the catalytic potential was evaluated in the epoxidation of a variety of olefins as well as allylic alcohols. Both catalysts showed essentially a constant activity after at least ten consecutive cycles. On the basis of the research above, a new type of magnetically separable catalyst was constructed by immobilization of lacunary-type phosphotungstate by hydrogen bonding between the sulfonate anion and silanol group on the surface of the coreshell magnetic nanoparticles. After the detailed characterization, the catalyst was used in the epoxidation of a variety of olefins and allylic alcohols and was found to possess high activity, selectivity towards epoxides, and a constant activity after at least ten catalytic recycles without solvent.